The present invention generally pertains to snap fasteners. More specifically, the present invention pertains to water migration resistant snap fasteners. In embodiments, a snap fastener has radial patterned circles of gripping protrusions which securely grip a fabric or substrate and resist water migration from one side of the fabric or substrate to an opposite side of the fabric or substrate in the area of the snap fastener. Embodiments of the present invention can be particularly useful when used with waterproof or water resistant fabrics or substrates. The snap fasteners can provide effective resistance to water migration while maintaining effective holding strength of the snap fasteners to the waterproof fabric or substrate. The present invention also pertains to related methods, such as methods of making and using water migration resistant snap fasteners.
Water or liquid migration resistance is desirable for snap fasteners used in outdoor applications, for example, military applications, and other applications in which the snap fasteners come into contact with water, moisture or other liquids. Water migration refers to water, moisture or other liquids passing from one side of a fabric to which the snap fastener is attached to the opposite side of the fabric.
Snap fasteners which resist water migration exist. However, existing snap fasteners which resist water migration can be improved. FIGS. 1-5 show and an existing snap fastener 10 which can resist water migration. Referring to FIG. 1, the existing snap fastener attachment 10 has a cap or snaptop 12, a female member or socket 14, a male member or stud 16 and another cap or snaptop 12. The snap fastener attachment 10, as with various ordinary snap fastener products, requires a spring action function for engagement. The spring action can be provided, for example, by a spring action engagement portion 18 on the stud 16 and/or a spring action engagement portion 20 on the socket 14. The spring action engagement portion can be incorporated into either the socket 14 or the stud 16 (together called mating members) or both. Referring to FIGS. 2-5, when the snaptop 12 engages with the socket 14, the fabric 22 is positioned between the snaptop 12 and the socket 14. Similarly, when the snaptop 12 engages with the stud 16, the fabric 22 is positioned between the snaptop 12 and the stud 16.
Referring to FIG. 2, a pre-attaching position of the stud 16, the snaptop 12 and the fabric 22 is shown. The pre-attaching position of the socket 14 is the same as the pre-attaching position of the stud 16 shown in FIG. 2. FIG. 3 shows a post 24 of the snaptop 12 penetrating through the fabric 22 and engaging the stud 16. FIG. 4 shows the snaptop 12 and the stud 16 clamped by an upper attaching die 26 and a lower attaching die 28. The post 24 is deformed by the upper and lower attaching dies 26, 28 to attach the snaptop 12 and the stud 16 to the fabric 22. The snaptop 12 and the socket 14 are attached to the fabric 22 similarly as the snaptop 12 and the stud 16. FIG. 5 shows an alignment position for engagement of the stud 16 and the socket 14 (mating members) after the stud 16 and socket 14 have been attached to the fabric 22.
The snap fastener attachment 10 of FIGS. 1-5 can provide some resistance to water migration when attached to the waterproof fabric 22 by squeezing the fabric 22 between opposed flat surfaces of the stud 16 and the snaptop 12 or the socket 14 and the snaptop 12. However, the flat opposed surfaces provides weak fabric holding or gripping power. Snap fasteners attached to waterproof fabric can also have plastic or rubber washers placed against the fabric side surfaces to enhance resistance to water migration. However, washers are additional components and require additional manufacturing steps and increase costs.
It is desirable for snap fasteners attached to the fabric to stay in the attached position without rotation or sideways movement. This requirement applies generally to snap fasteners, including the snap fasteners of FIGS. 1-5, plastic snap fasteners, metal snap fasteners, metal and plastic combined snap fasteners, and other types of snap products as well.
Ordinary snap fasteners, such as the snap fastener attachment 10 of FIGS. 1-5, tend to rotate relative to the fabric 22 or slide (move sideways) relative to the fabric 22. The snaptop 12 and the socket 14 attached to the fabric 22 and the snaptop 12 and the stud 16 attached to the fabric 22 tend to rotate and/or move sideways relative to the fabric 22 due to spring back, snap fastener geometric tolerances, and inconsistent snap fastener attaching strength. These movements tend to cause enlargement of the holes in the fabric 22 created when the posts 24 of the snaptops 12, 12 penetrate the fabric 22. Enlargement of the holes is undesirable and may result in the snap fastener attachment 10 coming off of the fabric 22. Also, enlargement of the holes can allow water and other liquids to easily migrate from one side of the fabric 22 to the opposite side.
Referring to FIGS. 6 and 7, attempts to address the problems of rotating and sliding of existing snap fasteners include placing several gripping pins 30 on one or more of the snap fastener surfaces which penetrate the fabric 22 to increase the gripping strength of the snap fastener. FIG. 7 shows a snap fastener stud 32 with the gripping pins 30 engaged and attached to the fabric 22. The gripping pins 30 can improve gripping of the fabric 22, such as for specific fabrics like silk, cotton, and knit. However when snap fasteners having gripping pins 30 are attached to waterproof fabrics 22, the gripping pins 30 damage the fabric 22 because the gripping pins 30 tend to penetrate into or even through the fabric 22. Water, moisture and other liquids can migrate through the areas of the fabric 22 penetrated by the gripping pins 30 which is contrary to the purpose of the waterproof fabric 22. Gripping pins 30 can increase the holding strength, but the gripping pins 30 diminish resistance to water migration. To counteract the holes created by the gripping pins 30 penetrating the waterproof fabric 22, plastic or rubber washers can be placed onto the post 24 of the snaptop 34 to resist water migration. However, washers may not be desirable as mentioned above. As can been seen in FIG. 7, the gripping pins 30 of the stud 32 and the gripping pins 30 of the snaptop 34 are positioned at the same radial distance from a centerline. Also, the gripping pins have a pin-like shape.
Accordingly, existing snap fasteners, particularly snap fasteners intended to resist water migration, have experienced problems and can be improved. Thus, needs exist to improve snap fasteners for the reasons mentioned above and for other reasons.